Goals: Pioneer 2 was intended to be a lunar orbiter. It carried an improved TV scanner for sending back images and a cosmic ray telescope designed to study the Cherenkov Effect (electromagnetic radiation).

Accomplishments:Despite improvements to its booster rockets, a malfunction left Pioneer 2 stranded in Earth orbit. Scientists managed to gather data about energy flux and micrometeroids before the spacecraft fell back to Earth after only 45 minutes in orbit.